ABSTRACT Restinga occurs as a narrow band of coastal habitats throughout the Atlantic Forest, although it presents considerable variation in vegetation structure, which likely contributes to heterogeneity in species inhabiting this endangered ecosystem. The goal of this study is to examine how variation in vegetation and abiotic conditions in the restinga ecosystem may contribute to heterogeneity of bird communities in Restinga de Jurubatiba, Brazil. Temperature, relative humidity, and vegetation structure were sampled to characterize four sites (dry forest, flooded forest, open scrub and closed scrub). Birds were sampled using observations, mist-netting and voice recordings. Results indicate that major differences of all variables occur between forest and scrub in both vegetation and birds. In addition, differences also exist within forests and within scrub, resulting in considerable heterogeneity among sampled areas. Scrub sites were richer in bird species (n = 58) than forest sites (n = 41), while closed scrub had the most species (n = 49). Also, 64% (47 of 73) of bird species were exclusive to forest or scrub habitats. Scrub habitats were more similar to each other than forest habitats. Normalized Difference Vegetation Index (NDVI) calculated from satellite images distinguished scrub sites and may be useful to monitor changes in vegetation patches through time. The restinga ecosystem is quite heterogeneous with considerable turnover in bird species composition and differences in vegetation structure. Forest strips may serve as connectors on the landscape and to help maintain species diversity and conservation of forest species. Also, this highly dynamic ecosystem, which includes a mosaic of habitat types, likely promotes resilience of bird populations under changing conditions.

Legitimate flowers visitors pollinate the flower during the visit and thus influence the production of fruits and seeds. We tested whether the visitation rate of potential pollinators is associated with the amount of seeds per fruit produced by the self-compatible bromeliad Tillandsia stricta (Bromeliaceae). We determined whether hummingbirds are legitimate visitors by testing for a correlation between visits and pollination (seed production) at the Guapiaçú Ecological Reserve (Reserva Ecológica de Guapiaçú), state of Rio de Janeiro. We tested 30 flowers, five of which were also monitored to test the possibility of spontaneous self-pollination. The remaining 25 flowers were exposed to floral visitors. Twenty-two flowers formed fruits and seeds, from which three formed seeds without floral visits. The hummingbird Amazilia fimbriata (Gmelin, 1788) was the only legitimate visitor. The average number (± standard deviation) of seeds was 27 units (±15) per fruit. The floral visitation rate by A. fimbriata was 6.6 (±3.4) visits/per flower. The number of floral visits and the amount of seed produced were positively correlated (r² = 0.58, p < 0.01). Thus, A. fimbriata is a legitimate floral visitor of T. stricta, and influences seed production per fruit in this bromeliad.

A proposta do presente estudo foi investigar a fenologia reprodutiva e a partilha de recurso floral (néctar) de Dahlstedtia pinnata (Benth.) Malme. (Fabaceae), endêmica de Mata Atlântica, entre beija-flores. Para a fenologia considerou-se a presença de estruturas reprodutivas nas plantas e para a partilha de recurso floral foi examinada a frequência de potenciais polinizadores e comportamentos de forrageamento. Este estudo foi conduzido no Parque Estadual da Pedra Branca, no estado do Rio de Janeiro, em floresta ombrófila densa, entre agosto de 2010 e agosto de 2011. A floração ocorreu entre dezembro de 2010 e março de 2011, e a frutificação entre abril e junho de 2011. Os horários de forrageamento dos beija-flores diferiram significativamente, com visitas legítimas às flores ocorrendo pela manhã, e ilegítimas no final da manhã e à tarde. Cinco espécies de beija-flores visitaram flores, três delas como visitantes legítimos:Phaethornis ruber, P. pretrei eRamphodon naevius. Amazilia fimbriata e fêmeas de Thalurania glaucopis realizaram apenas visitas ilegítimas. Phaethornis ruber pilhou néctar (78% de visitas ilegítimas, n=337). Ramphodon naevius, com comportamento de forrageamento territorial e um tamanho corporal superior às demais espécies de beija-flores observadas, dominou as visitas florais. Isso sugere que D. pinnata é um recurso alimentar importante para essa ave endêmica de Mata Atlântica e globalmente categorizada como Quase Ameaçada.

The purpose of this study was to investigate the reproductive phenology and sharing of floral resource (nectar) ofDahlstedtia pinnata (Benth.) Malme. (Fabaceae), endemic of Atlantic forest, among hummingbirds. For the phenology, we looked at the presence of reproductive structures in the plants, and for floral resource sharing, the frequency of potential pollinators and foraging behaviors were examined. This study was conducted in Pedra Branca State Park, in state of Rio de Janeiro, in a dense ombrophilous forest, between August 2010 and August 2011. Flowering occurred between December 2010 and March 2011, and fruiting between April and June 2011. Hummingbirds' foraging schedules differed significantly, with legitimate visits to the flowers occurring in the morning and illegitimate visits occurring during late morning and the afternoon. Five species visited flowers, three of which were legitimate visitors:Phaethornis ruber, P. pretrei, andRamphodon naevius. Amazilia fimbriata andThalurania glaucopis females only visited illegitimately.Phaethornis ruber robbed nectar (78% of illegitimate visits, n=337). Ramphodon naevius, with a territorial foraging behavior and a body size bigger than that of other observed hummingbird species, dominated the floral visits, which suggests thatD. pinnata is an important nourishing resource for this endemic bird of the Atlantic forest, currently globally categorized as Near Threatened.